JPH0253454B2 - - Google Patents

Abstract

The invention relates to a process for the production of an object from a granular ABS polymer composition, said composition comprising a mixture of I 10-98 parts by weight of one or more graft copolymers obtained by polymerizing a mixture of one or more unsaturated nitriles and one or more vinylaromatic compounds in the presence of a rubber. II 2-90 parts by weight of a copolymer of one or more unsaturated nitriles and one or more vinylaromatic compounds, and III 0-20 parts by weight of one or more additives, wherein the polymer composition is melted, homogenized, and extruded or injection molded into an object. To improve the flow properties of the mixture introduced into the processing equipment and the throughput of this equipment the invention is characterized in that the ratio between the average particle size (by weight) of the copolymer II to the average particle size (by weight) of the graft copolymer I exceeds 1.5.

Description

[Detailed description of the invention]

The present invention is a) ABS graft copolymer 50-90
parts by weight,) 10 to 50 parts by weight of a copolymer consisting of one or more unsaturated nitriles and one or more vinyl aromatic compounds, and) 1
A process for melting, homogenizing, and extrusion or injection molding of a particulate ABS polymer composition to produce an article comprising 0 to 20 parts by weight of one or more additives; In some cases, the product is obtained directly from the components of the particulate polymer composition. Unsaturated nitriles here mean all organic compounds containing a carbonitrile group and one or more unsaturated carbon bonds. Examples are acrylonitrile and methacrylonitrile. Metals have been widely replaced by plastics in the majority of products, such as plumbing for drainage, water supply, heating, etc. Polyvinyl chloride (PVC) is one type of plastic that is very widely used in plumbing, especially sewage piping. However, in many pipe applications it is not possible to use PVC because of insufficient strength or heat resistance. The automobile industry is also increasingly replacing plastics, especially as their cost and weight advantages are important. ABS is a type of plastic widely used in the automotive industry where PVC lacks strength or heat resistance. ABS has impact resistance, rigidity,
High standards can be imposed in terms of heat resistance and color strength. Mostly ABS is a graft copolymer obtained by polymerizing a mixture of styrene and acrylonitrile in the presence of a rubber such as polybutadiene, SBR, etc. Generally, ABS polymer compositions contain separately produced amounts of copolymers of styrene and acrylonitrile. Composition manufacturers' usual practice when producing ABS polymer compositions is to first combine all ingredients, such as graft copolymer(s), copolymer(s), additives, and pigments. mixing and then homogenizing and granulating this final composition. The granules are then melted by a processor and shaped into shaped articles by extrusion or injection molding. In principle, ABS polymer compositions are always difficult to process into molded articles directly from their constituent components. There are two major reasons for this. The first
The key is that products made from ABS polymer compositions must always meet extremely strict standards regarding color and mechanical properties, so that each lot is specially manufactured to order. The second reason is that in order to process ABS into molded parts that meet the required high standards in terms of surface and other properties, special equipment is required in connection with the mixture of the various components and the homogeneity of the product. That's true. Furthermore, feeding the components of the polymer composition to extrusion or injection molding equipment requires special equipment. The object of the present invention is to manufacture products from ABS polymer compositions, starting without using pre-manufactured granules, but using the individual components that make up this polymer composition, and using conventional rigorous The goal is to find a method that allows products to meet specific standards. Another object of the invention is to obtain a method in which the flow properties of a mixture introduced into the feed of an extruder or injection molding device are improved. Yet another object of the invention is to provide a method in which the throughput of an extruder or injection molding device is increased over conventional methods. Said object of the invention is to provide a method as described above, wherein said granular composition has a particle size distribution with at least two peaks, and the ratio between the particle sizes at said peaks is greater than 1.5, and advantageously 2. upper part,
and the particulate polymer composition is selected from the group consisting of A particulate polymer having an average particle size of 60 to 250 μm; B particulate polymer having an average particle size of 200 to 500 μm; and C particulate polymer having an average particle size of 1000 μm or more. This is achieved by a method characterized in that it is obtained by mixing at least two components. In this case, components A, B and C are each separate components,
or corresponding to or a component thereof, and all two or three thereof may be at least one of A, B and C. Generally, the ratio between the particle sizes in the peaks does not exceed 75, since above this value there can be a risk of mixture separation. It should be noted in this connection that all particle size distributions or average particle sizes stated are by weight. Advantageously, the amount of A (if present) is between 2.5 and
80% by weight, the amount of B (if present) is 2.5~
80% by weight, and the amount of C (if present) from 2.5 to 80% by weight. It has surprisingly been found that when using the method according to the invention it is possible to produce products such as pipes or automobile parts directly from the components of the polymer composition. In an advantageous embodiment of the process according to the invention, a mixture comprising at least 50% by weight of a graft copolymer having an average particle size of 75 to 200 μm and 50% or less by weight of a copolymer having an average particle size of 200 to 400 μm is provided. used. More particularly, at least 10% by weight of said copolymer is present. In another advantageous embodiment, the average particle size is 1000 μm
The amount of particulate polymer having more than 2.5% by weight. Advantageously, the polymer may be a masterbatch in which one or more additives or pigments are incorporated into the polymer. Generally, the average particle size of particulate polymers having an average particle size of 1000 μm or more does not exceed 5000 μm. An advantageous range is 2000-4000 μm. Advantageously, the amount of particulate polymer having an average particle size of 60 to 250 μm is not less than 10% by weight. These components of the polymer composition can be fed to the extruder or injection molding equipment in the form of "premixes" or as separate feed streams. Generally, a crammer feeder (crammer--
A hopper containing a feeder is provided. It is therefore possible to feed the polymer composition to the hopper as a premix of all components. This premix can be manufactured by blending all the ingredients together in a conventional manner. If a premix is used, this is advantageously produced immediately before said feeding to the hopper. It is also possible to feed all components separately to the hopper. In this case, the two or more feed streams to the hopper are mixed by homogenization in an extruder or injection molding device. If at least two separate feed streams are introduced into the hopper and into the extruder or injection molding apparatus, one or more of said streams may actually be a premix of two or more components. It's totally possible. For example, in an advantageous embodiment, the particulate polymer having an average particle size of 1000 μm or more may be a master batch of one or more additives, optionally containing pigments. Further, the masterbatch and a powder having a smaller average particle size, for example, in the range of 60 to 250 μm and/or in the range of 200 to 500 μm, may also be used.
It is also possible to supply premixes with one or more polymers. This mixture is preferably prepared immediately before melting and homogenization, since otherwise there is a risk that the mixture would block the feed. This mixing may be carried out in a Henschel (RTM)-type mixer or in a hopper on the feed opening of an extruder or injection molding device. In another embodiment of the process according to the invention, the polymer composition fed to the extruder consists of copolymer beads containing graft copolymer powder and optionally a small amount of masterbatch. If separate feed streams are fed to the extruder or hopper, the particle size distribution is calculated as if all components were mixed before feeding. The method according to the invention can be carried out using any type of extruder or injection molding equipment, such as a single screw extruder,
Suitable for cascade extruders, twin screw extruders and all types of injection molding machines. In the case of twin-screw extruders, the main advantage of the present invention is the increased throughput of the polymer composition; in other cases the improved flow properties are also of great importance. A related point is that it is unnecessary to use a crumber feeder in a hopper to increase the amount of polymer introduced into the melt zone of an extruder or injection molding device. be. In some cases, especially if the product flow characteristics are very poor, a Cramer feeder is useful. The exact amounts of ingredients, ie graft copolymer, copolymer and additives, to be used will vary depending on the desired properties of the product. This ABS polymer composition comprises 50 to 90 parts by weight of the graft copolymer, 10 to 50 parts by weight of the copolymer, and 1
0 to 20 parts by weight of one or more additives. Graft copolymers are made by polymerizing a monomer mixture in the presence of rubber. Generally, this monomer mixture contains one or more of the following components: styrene and/or derivatives of styrene, such as halogenated styrene and α-
It consists of methylstyrene; acrylonitrile and/or methacrylonitrile; acrylic esters such as ethyl acrylate, methyl acrylate and methyl methacrylate; maleic anhydride. As rubber, any rubber suitable for the production of ABS can be used. Representative examples of these rubbers are polybutadiene, butadiene-styrene rubber, butadiene-acrylonitrile rubber, acrylate rubber, ethylene-propylene or ethylene-propylene-diene rubber, ethylene-vinyl acetate, and chloroprene rubber. The graft copolymers can be prepared by conventional batch, semi-continuous or continuous polymerization methods, such as emulsion, suspension, bulk or solution polymerization. Also,
Combinations of these methods can also be used. The copolymer may be made from the same monomer mixture used in the graft copolymer. However, this is not necessary. Generally, the monomers used to make the copolymers are selected from the group that has also been used to make the graft copolymers. The copolymer can be made using the methods described above. The polymer composition can contain conventional additives. These additives include antioxidants, UV stabilizers, lubricants, fillers, antistatic agents, flame retardants, blowing agents, and the like. It is also possible to incorporate certain amounts of one or more polymers, for example polyvinyl chloride, polyphenyl oxide or polycarbonate, into the polymer composition. The particle size of particulate polymers is related to the type of manufacturing method. The average particle size is approximately 60 to 400 μm using the emulsification method, and 200 to 800 μm using the suspension method. If granules are used, average particle size 1000-6000μm
It should be within the range of The average particle size can be reduced by crushing or milling if necessary to obtain the desired average particle size. The method according to the invention can be used for the production of all types of products. In particular, these products are tubes, plates and profiled parts. As a rule, these products are manufactured by extrusion or coextrusion. It is also possible to produce foam products with this method. Additionally, extrusion- or injection-blow molding methods can be used to produce plastic products. Finally, it is possible to manufacture the product by injection molding methods. In the following, the present invention will be explained in detail with reference to examples. Example 1 The flow properties of a number of molding mixtures were investigated by measuring the time required for a given amount of product introduced into the funnel to exit the funnel. The following products were tested: A: Emulsion graft copolymer of styrene and acrylonitrile based on butadiene rubber with an average particle size of about 160 μm. B: Suspension polymer of styrene and acrylonitrile with an average particle size of about 400 μm. C: A mixture consisting of 70 parts by weight of A and 30 parts by weight of B. The results are summarized in the table below. The same test was carried out using the same product and after mixing the product with customary additives (2 parts by weight). The results are summarized in the table below.

TABLE From this table it is clear that a beneficial mutual effect on the flow properties results. When fed to the hopper of a tube extrusion process, product A could not be processed into tubes due to feeding difficulties, but product C could be processed at large extrusion rates without any difficulties. Example 2 96 parts by weight of ABS powder with an average particle size of approximately 120 μm,
and 4 parts by weight of a masterbatch of carbon black/additives in styrene-acrylonitrile copolymer having an average particle size of 3000 μm was fed into a modified injection molding machine. Although the flow characteristics of the ABS powder were not very good (drying flow for 40 seconds), there were no difficulties in feeding the material in the molding machine. The product could be manufactured at high speed. These products had a homogeneous distribution of carbon black so that no powder and granulate segregation occurred. Example 3 Two separate feed streams were fed into the hopper of an injection molding machine, one consisting of beads of styrene-acrylonitrile copolymer and the other consisting of granules of ABS graft copolymer. A homogeneous product with excellent mechanical properties was obtained at high speed.

Claims (1)

[Claims] 1. A copolymer consisting of 50 to 90 parts by weight of one or more graft copolymers of ABS, one or more unsaturated nitriles, and one or more vinyl aromatic compounds. melting a granular ABS polymer composition comprising 10 to 50 parts by weight and 0 to 20 parts by weight of one or more additives;
A method for producing plastic articles obtained directly from the components of said granular polymeric composition by homogenization and extrusion or injection molding into articles, said granular composition having a particle size distribution having at least two peaks. and the ratio between the particle sizes at the peak is more than 1.5, and the granular polymer composition has: A a granular polymer having an average particle diameter of 60 to 250 μm; B a granular polymer having an average particle diameter of 200 to 500 μm and C. A method for producing a plastic product, characterized in that it is obtained by mixing at least two components selected from the group consisting of granular polymers having an average particle size of 1000 μm or more. 2. characterized in that the particle size ratio is greater than 2;
A method according to claim 1. 3. Process according to claim 1, characterized in that A, B and C are each used in amounts of 2.5 to 80% by weight. 4. At least 50% by weight of a granular graft copolymer having an average particle size of 75 to 200 μm;
2. Process according to claim 1, characterized in that a mixture is used which contains up to 50% by weight of particulate copolymers having a particle diameter of 200 to 450 .mu.m. 5. Claim 1, characterized in that said mixture is produced immediately before melting and homogenization.
The method described in section. 6. Characterized by the presence of at least 10% by weight of a particulate copolymer having a particle size of 200 to 500 μm,
A method according to claim 1. 7. Process according to claim 1, characterized in that at least 2.5% by weight of particulate polymer having an average particle size of 1000 μm or more is used. 8. A masterbatch comprising one or more additives mixed into the copolymer or graft copolymer is used as the granular polymer having an average particle size of 1000 μm or more. Any 1 from range 1 to 7
The method described in section. 9. The method according to any one of claims 1 to 8, characterized in that the average particle size of the granular polymer having an average particle size of 1000 μm or more does not exceed 5000 μm. 10. The method according to claim 9, characterized in that the particle size is 2000 to 4000 μm. 11. A method according to any one of claims 1 to 10, characterized in that the particle size ratio does not exceed 75.